The present invention relates to a device for adjusting a camshaft of an internal combustion engine according to the introductory clause of the main claim.
Such a device is known from PCT/EP 2008/006417 of the applicant and describes how an actuating element (typically a tappet or suchlike actuating pin) can generate an axial, predetermined adjustment of the camshaft by interacting with a profile associated with the camshaft. This is relevant in particular for such cases of application in which various cam tracks are to be associated in a switchable manner to a combustion engine.
It is known from the prior art here from DE 196 11 641 C1 to provide for each axial movement position of the lift profile arrangement a suitably driven pin which can then generate a respectively intended axial movement. However, this is structurally complex and requires a large amount of installation space at the site of use.
From PCT/EP 2008/006417 which is drawn upon generically, it is known in addition to form the lift profile with a plurality of control grooves for interaction with the electromagnetically driven tappet unit so that the control grooves can penetrate into various groove depths and hence through various penetration depths (to be set in a suitable manner) of the tappet unit, can actuate the camshaft in the respectively desired manner.
However, the tappet unit known from the generic prior art, together with the electromagnetic actuating device interacting therewith, is structurally complex, because to realize the known groove engagement functionality in two penetration depths, the known tappet unit has an arrangement consisting of an inner tappet (of smaller diameter) and an outer tappet, surrounding the latter, of larger diameter, which are associated with the respective control grooves and the corresponding penetration depth.
It is therefore necessary to realize the movement behaviour of the inner and outer tappets of the known device in a suitable manner with regard to construction and technical control, which is costly and potentially prone to error.
The object of the present invention is therefore to improve a device for adjusting a camshaft according to the introductory clause of the main claim with regard to a simplified structural realization, hence potentially increased operating reliability and reduction of the required expenditure on components and assembly.